1. Field of the Invention
This invention relates to a solid electrolyte, and more particularly, to a flame-retardant solid electrolyte which is applicable to secondary cells which are high in energy density and safety.
2. Description of the Prior Art
There is a great demand for secondary cells which have a high energy density in order to realize small-size and lightweight portable appliances.
In order to lower environmental pollution ascribed to exhaust gases from automobiles, many attempts have been made to put electric vehicles into practice. However, to realize electric vehicles requires the development of cells which have an energy density higher than existing lead batteries.
Technical developments have now been made in order to obtain cells or batteries which have a high energy density. In the event that such a high energy density cell suffers short-circuiting, the high energy of the cell is discharged at one time. Hitherto, it is usual to avoid the problem caused by overcharging, overdischarging or external short-circuiting by use of an outside safety mechanism. However, where short-circuiting occurs in the inside of a cell, the outside safety mechanism does not work appropriately.
Accordingly, it becomes necessary to develop a safety cell which does not rely on an outside safety mechanism.